Thread for Non-CA Academic Questions

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Re: Thread for Non-CA Academic Questions

Post by gameoflifeboy » December 2nd, 2017, 1:47 pm

As the quartic equation Ax^4 + Bx^3 + Cx^2 + Dx + E = 0 can be reduced to x^4 + (B/A)x^3 + (C/A)x^2 + (D/A)x + (E/A) = 0 without loss of information (unless A is 0), you can just do a trivial substitution on the formulas Macbi gave to find its solutions:

Code: Select all

a -> B/A
b -> C/A
c -> D/A
d -> E/A
Expanding the formula into a standard form, of course, is another matter. I used to amuse myself doing these by hand when I was 13, but now I am too busy for it.

So even without consulting Mathematica, it is trivial to see that exists such a formula--but when you asked "is there a formula," maybe you meant "has the formula ever actually been written, and simplified." My answer is "probably; I could easily imagine someone like me doing this." Calcyman's formulas don't seem to be simplified thoroughly, though; they still contain square roots and cube roots of non-polynomial rational expressions, as well as sums of fractions having different denominators. I think that if the formula were to be entirely simplified, no term but A would be taken to a power higher than the fourth. (In the expanded cubic formula, no term but A has an exponent higher than 3.) If provable, this would work as a good test to see whether an evaluation by hand was correct.

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Re: Thread for Non-CA Academic Questions

Post by Majestas32 » December 2nd, 2017, 4:18 pm

Can somebody give me an overview of data types in Python?
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Re: Thread for Non-CA Academic Questions

Post by AbhpzTa » December 4th, 2017, 1:08 pm

AforAmpere wrote:
muzik wrote:Is 11 truly the only number where n, n+2, n+6, n+8, n+90, n+92, 9+96, n+98, n+180, n+182, n+186 and n+188 are all prime? If there are any more such numbers out there I will be surprised.
Probably not, as calcyman said, but none that I could find up to 10^8.
No others < 304075581810 = 29# * 47 .
Iteration of sigma(n)+tau(n)-n [sigma(n)+tau(n)-n : OEIS A163163] (e.g. 16,20,28,34,24,44,46,30,50,49,11,3,3, ...) :
965808 is period 336 (max = 207085118608).

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Re: Thread for Non-CA Academic Questions

Post by AforAmpere » December 4th, 2017, 6:13 pm

AbhpzTa wrote: No others < 304075581810= 29# * 47 .
What did you use to check?
I and wildmyron manage the 5S project, which collects all known spaceship speeds in Isotropic Non-totalistic rules.

Things to work on:
- Find a (7,1)c/8 ship in a Non-totalistic rule
- Finish a rule with ships with period >= f_e_0(n) (in progress)

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Re: Thread for Non-CA Academic Questions

Post by AbhpzTa » December 5th, 2017, 10:18 am

AforAmpere wrote:
AbhpzTa wrote: No others < 304075581810= 29# * 47 .
What did you use to check?
Excel and Notepad (and this page).
No others < 433469446410 = 29# * 67 .
Iteration of sigma(n)+tau(n)-n [sigma(n)+tau(n)-n : OEIS A163163] (e.g. 16,20,28,34,24,44,46,30,50,49,11,3,3, ...) :
965808 is period 336 (max = 207085118608).

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Re: Thread for Non-CA Academic Questions

Post by muzik » December 5th, 2017, 9:26 pm

I've finally found a way to accurately graph them.

Are there any well-known names for these shapes - the "bubble polygons", as I like to call them? They definitely seem to resemble different types of torus knot, without the whole over/under thing, since we're dealing with extending the definition of a star polygon here.

Image
Image
Image
Image
Image
Image

In order: {3/2}, {5/3}, {5/4}, {6/5}, {7/4}, {7/5}, assuming we're going with regular star polygon notation.
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Re: Thread for Non-CA Academic Questions

Post by gameoflifemaniac » December 9th, 2017, 5:47 am

What are signed trees? http://oeis.org/A000060
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Re: Thread for Non-CA Academic Questions

Post by Gamedziner » December 9th, 2017, 9:38 am

I have a conjecture, but I don't know how to prove it:
[∑̊₌₁ aₙ×sin(bx+c)]≠k for all real values of x and a finite positive integer o, where each a, b, and k are constant, non-zero real numbers, and each c is any constant real number.

In other words, I conjecture that you can't use add sine waves alone to get a constant, non-zero value.

I base this upon the nature of the universe: If we could do this, then we could probably use waves to produce a permanent higher-energy state. Such a state would limit the effects of entropy, thereby testing the bounds of the Second Law of Thermodynamics.

EDIT: Thanks calcyman! I now have a proof:
Consider the following infinite integral:
Image
Upon dividing by b then subtracting c from the top and bottom parts of the equation, we have an equivalent form that works for all terms. Zero times any real number is zero, and zero plus zero is zero, so the entire sum is also zero. The function, when used on zero, also produces 0.
Let f~(f(x))=x.
Let f(x) be the integral described above.
Since f(0)=0, f[f(0)]=0.
f~{f[∑̊₌₁ aₙ×sin(bx+c)]}=f~{f[f(0)]}
[∑̊₌₁ aₙ×sin(bx+c)]=[f(0)]=0
Since k≠0, this proves the proposition.

Also, as corollaries, sin² x and cos² x cannot be produced under the same conditions, either.
Last edited by Gamedziner on December 9th, 2017, 6:32 pm, edited 1 time in total.

Code: Select all

x = 81, y = 96, rule = LifeHistory
58.2A$58.2A3$59.2A17.2A$59.2A17.2A3$79.2A$79.2A2$57.A$56.A$56.3A4$27.
A$27.A.A$27.2A21$3.2A$3.2A2.2A$7.2A18$7.2A$7.2A2.2A$11.2A11$2A$2A2.2A
$4.2A18$4.2A$4.2A2.2A$8.2A!

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Re: Thread for Non-CA Academic Questions

Post by calcyman » December 9th, 2017, 9:53 am

Gamedziner wrote:I have a conjecture, but I don't know how to prove it:
[∑̊₌₁ aₙ×sin(bx+c)]≠k for all real values of x and a finite positive integer o, where each a, b, and k are constant, non-zero real numbers, and each c is any constant real number.

In other words, I conjecture that you can't use add sine waves alone to get a constant, non-zero value.

I base this upon the nature of the universe: If we could do this, then we could probably use waves to produce a permanent higher-energy state. Such a state would limit the effects of entropy, thereby testing the bounds of the Second Law of Thermodynamics.
Integrate both sides of your equation. The left-hand side is bounded, and the right-hand side is linearly increasing.
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Re: Thread for Non-CA Academic Questions

Post by muzik » December 18th, 2017, 8:16 am

Are there any ways to infinitely tesselate space in a way that would normally close over and create a polyhedron?
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Re: Thread for Non-CA Academic Questions

Post by muzik » December 21st, 2017, 4:31 am

Still waiting on answers to both questions.
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Re: Thread for Non-CA Academic Questions

Post by gameoflifeboy » December 23rd, 2017, 5:58 pm

muzik wrote:Do there exist any polyhedra which are isohedral, isogonal and isotoxal, but the individual faces aren't regular?
I don't think so, but for Euclidean tilings the following construction counts:

http://mathstat.slu.edu/escher/upload/e ... nd-net.png

After further consideration, I believe that the requirements cannot be satisfied by a finite polyhedron. Any finite polyhedron obeying these requirements would have all its vertices lying on the same sphere (as a consequence of isogonality), and all its edges would be the same length (as a consequence of isotoxality). Since each face of the polyhedron must fulfill the same requirements, the faces would all have edges the same length, and vertices lying on the same circle. Thus, all angles on a single face must be congruent. Since the edges are also the same length, it follows that each face must be a regular polygon, contradicting the requirement that the faces aren't regular.
muzik wrote:What happens if the pentagrams in the great stellated dodecahedron are made into pentagons following the same vertices?
They become the pentagons of the ditrigonal dodecadodecahedron, or of the great ditrigonal icosidodecahedron, and do not meet at edges anymore, although they still come three to a vertex.

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Re: Thread for Non-CA Academic Questions

Post by muzik » January 10th, 2018, 6:03 am

Is it possible for a tessellation to have a negative amount of polytopes or vertices?

Using the equation 720/(360-(V*A)), where V is the amount of polygons meeting to an edge and A is the internal angle of said polygon, to give the amount of vertices gives expected results for the platonic solids and infinity for what would make euclidean tilings, but hyperbolic tilings give negative results. The heptagonal tiling has -28 vertices whereas its dual has -12, the octagonal tiling has -16 vertices and its dual -6, and the infinity-gon tiling has -4 vertices with its dual theoretically having negative infinity.
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Re: Thread for Non-CA Academic Questions

Post by gameoflifemaniac » January 19th, 2018, 2:21 pm

The hyperoperarions are incrementation, addition, multiplication, exponentiation, tetration, pentation etc. But is there something past incrementation, or is it so elementary, that it can't be divided further?
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Re: Thread for Non-CA Academic Questions

Post by Macbi » January 19th, 2018, 3:32 pm

gameoflifemaniac wrote:The hyperoperarions are incrementation, addition, multiplication, exponentiation, tetration, pentation etc. But is there something past incrementation, or is it so elementary, that it can't be divided further?
This is a great question. But I've always thought the incrementation operation is itself a bit dodgy. In particular 3 + 0 = 3 and 4 + 0 = 4. So 3 incremented with itself 0 times should be 3, and 4 incremented with itself 0 times should be 4, but a 0-ary function doesn't take any inputs so it should always take on the same value.

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Re: Thread for Non-CA Academic Questions

Post by gameoflifemaniac » January 19th, 2018, 4:31 pm

Macbi wrote:
gameoflifemaniac wrote:The hyperoperarions are incrementation, addition, multiplication, exponentiation, tetration, pentation etc. But is there something past incrementation, or is it so elementary, that it can't be divided further?
This is a great question. But I've always thought the incrementation operation is itself a bit dodgy. In particular 3 + 0 = 3 and 4 + 0 = 4. So 3 incremented with itself 0 times should be 3, and 4 incremented with itself 0 times should be 4, but a 0-ary function doesn't take any inputs so it should always take on the same value.
Oops, I meant zeration. Sorry!
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Re: Thread for Non-CA Academic Questions

Post by A for awesome » January 19th, 2018, 6:00 pm

gameoflifemaniac wrote:
Macbi wrote:
gameoflifemaniac wrote:The hyperoperarions are incrementation, addition, multiplication, exponentiation, tetration, pentation etc. But is there something past incrementation, or is it so elementary, that it can't be divided further?
This is a great question. But I've always thought the incrementation operation is itself a bit dodgy. In particular 3 + 0 = 3 and 4 + 0 = 4. So 3 incremented with itself 0 times should be 3, and 4 incremented with itself 0 times should be 4, but a 0-ary function doesn't take any inputs so it should always take on the same value.
Oops, I meant zeration. Sorry!
http://math.eretrandre.org/tetrationfor ... hp?tid=122
x₁=ηx
V ⃰_η=c²√(Λη)
K=(Λu²)/2
Pₐ=1−1/(∫^∞_t₀(p(t)ˡ⁽ᵗ⁾)dt)

$$x_1=\eta x$$
$$V^*_\eta=c^2\sqrt{\Lambda\eta}$$
$$K=\frac{\Lambda u^2}2$$
$$P_a=1-\frac1{\int^\infty_{t_0}p(t)^{l(t)}dt}$$

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Re: Thread for Non-CA Academic Questions

Post by gameoflifemaniac » January 30th, 2018, 8:19 am

So, you randomly choose bits n times. You add up the bits and make a plot of how many times a number appeared. What distribution is this?
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Re: Thread for Non-CA Academic Questions

Post by Macbi » January 30th, 2018, 8:22 am

gameoflifemaniac wrote:So, you randomly choose bits n times. You add up the bits and make a plot of how many times a number appeared. What distribution is this?
https://en.wikipedia.org/wiki/Binomial_distribution?

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Re: Thread for Non-CA Academic Questions

Post by gameoflifemaniac » January 30th, 2018, 9:48 am

Macbi wrote:
gameoflifemaniac wrote:So, you randomly choose bits n times. You add up the bits and make a plot of how many times a number appeared. What distribution is this?
https://en.wikipedia.org/wiki/Binomial_distribution?
Thank you! This makes sense!
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Re: Thread for Non-CA Academic Questions

Post by gameoflifemaniac » March 6th, 2018, 4:53 pm

How many different patterns are possible in those pattern lockers, those that are common in phones?
Attachments
Example of pattern
Example of pattern
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Re: Thread for Non-CA Academic Questions

Post by Majestas32 » March 6th, 2018, 5:24 pm

I remember a YouTube video that said it was like 110000
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Re: Thread for Non-CA Academic Questions

Post by Gamedziner » March 6th, 2018, 6:09 pm

gameoflifemaniac wrote:How many different patterns are possible in those pattern lockers, those that are common in phones?
389,112.

Source

Code: Select all

x = 81, y = 96, rule = LifeHistory
58.2A$58.2A3$59.2A17.2A$59.2A17.2A3$79.2A$79.2A2$57.A$56.A$56.3A4$27.
A$27.A.A$27.2A21$3.2A$3.2A2.2A$7.2A18$7.2A$7.2A2.2A$11.2A11$2A$2A2.2A
$4.2A18$4.2A$4.2A2.2A$8.2A!

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Re: Thread for Non-CA Academic Questions

Post by gameoflifemaniac » March 20th, 2018, 2:29 pm

What is the optimal number system (fewest # of digits and data)?
How many patterns are there that have a bounding box x*y?
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Re: Thread for Non-CA Academic Questions

Post by Majestas32 » March 20th, 2018, 4:40 pm

Ternary, and approximately 2^(xy-3)
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